At a Glance

Relevant expertise/areas of interest:

functional MRI

two photon fluorescence microscopy

neurovascular unit

Alzheimer’s disease

stroke recovery

traumatic brain injury imaging

Short Bio

Dr. Stefanovic is a Tier 1 Canada Research Chair in Functional Neuroimaging, a senior scientist in Physical Sciences at Sunnybrook Research Institute, and an associate professor in the Department of Medical Biophysics at the University of Toronto. Dr. Stefanovic’s research focuses on the development of new methods for quantitative in vivo imaging of brain function, including high field functional MRI, two-photon fluorescence microscopy, and extracellular recordings for tracking function of cellular components of the neurovascular unit over the course of neurodegeneration in transgenic models of Alzheimer’s Disease, during chronic stage of recovery in rodent models of focal ischemia, and following traumatic brain injury.

Research/Teaching

Research Synopsis

Brain Function Imaging

The broad aim of our research is the understanding of human brain function. Over the past few decades, new techniques have been developed that, for the first time, have allowed completely noninvasive examination of the working human brain in real time and with exquisite spatial detail. Functional magnetic resonance imaging (fMRI), in particular, has become the dominant method of studying human brain function. Despite its widespread use by neuroscientists and clinicians in healthy subjects and patients, the full potential of fMRI is yet to be realized and is arguably predicated on our arriving at a detailed understanding of the physical and physiological processes behind fMRI.

Like a number of other modalities, fMRI provides an indirect measure of neuronal activity, fMRI signal being dictated by the changes in brain vasculature during subject's stimulation. Accordingly, we are particularly interested in the coupling between local neuronal activity and the state of the surrounding vasculature. On one hand, we are working on the development of novel, quantitative magnetic resonance imaging based techniques for human brain function imaging. On the other, we are using in vivo multiphoton microscopy in combination with various fluorescent markers and pharmacological agents for very detailed characterization of the neuronal and vascular response to brain stimulation in animals. In both human and animal studies, we also employ electrophysiological recordings for a more direct assessment of the local neuronal activity. Finally, we're developing new theoretical models to incorporate these multimodality data, all aimed at furthering our understanding of the biophysics of brain functioning and facilitating the translation of basic science research to various clinical applications, such as stroke, trauma, and Alzheimer's Disease.